Dietary Phytoestrogens and Lung Cancer Risk

Abstract

IETARY PHYTOESTROGENS ARE plant-derived nonsteroidal compounds with weak estrogen-like activity. Most phytoestrogens exist in the diet as inactive compounds and, following consumption, undergo enzymatic conversion in the gastrointestinal tract, resulting in the formation of compounds with a steroidal structure similar to that of estrogens. 1 Phytoestrogens are subdivided into 3 main classes: isoflavones, lignans, and cumestrans. The isoflavones and the lignans are the 2 main groups of hormone-like diphenolic dietary phytoestrogens. On ecologic analysis, both have been found in high levels in the plasma of individuals living in areas with relatively low cancer incidence. 2 Isoflavones are the most common form, and most extensively investigated, of the phytoestrogens. The 2 major forms of isoflavones, genistein and daidzein, are formed from the precursors genistin and daidzin and are found in a variety of sources, including soy products, soybeans, chickpeas, and red clover. 2,3 The lignan metabolites, enterolactone and enterodiol, are formed from the precursors matairesinol and secoisolariciresinol. Lignans are derived from rye grains, linseeds, carrots, tea, spinach, broccoli, and other vegetables. 1,2 Coumesterol is the predominant estrogenic phytoestrogen in the cumestran group and is mainly found in beans, peas, clover, spinach, and sprouts. 4 A fourth group of plantderived steroidal compounds that is believed to have estrogenic properties are See also pp 1505 and 1550.

Luteolin inhibits invasion of prostate cancer PC3 cells through E-cadherin

“…The effects of dietary flavonoids are of great interest due to their potential in cancer prevention (41,42). For example, in a 25-year follow-up study on 9959 Finnish men, dietary intake of flavonoids was inversely associated with the incidence of cancer at all sites combined (43).…”

Dietary intakes and food sources of phytoestrogens in the European Prospective Investigation into Cancer and Nutrition (EPIC) 24-hour dietary recall cohort

“…Therefore, potential effects on hormone-related diseases such as breast, prostate, colorectal and endometrial cancers; and also on lung cancer, CVD, osteoporosis and menopausal symptoms, have been suggested. 4,8,10 Furthermore, phytoestrogens may reduce oxidative stress by activating intracellular kinase cascades, leading to acute activation of endothelial nitric oxide synthase and modulating redox-sensitive gene transcription via NF-kB (nuclear factor-kB) and Nrf2 (nuclear factor erythroid 2-related factor 2). 11,12 A meta-analysis investigating the relationship between soy foods, isoflavone intakes and breast cancer showed an inverse association in Asian populations, but not in Western populations (Europe and US), 13 which tend to have low phytoestrogen intake.…”

A review of the Hispanic paradox: time to spill the beans?

“…Here we present data to suggest that the increased consumption of high-fibre foods such as legumes, primarily in the form of beans, may provide an alternate explanation for the Hispanic paradox [43,48,[52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67]. Data on bean consumption shows that Hispanic subjects, who represent 11% of the USA population, are the largest consumers of beans (accounting for 33% of all consumption) [52].…”

“…Several studies have linked a lower incidence of lung cancer to the consumption of phyto-oestrogens, suggesting that the oestrogenic effect of this food group may confer hormonal protective effects [54][55][56][57][58]. In a very detailed analysis of the dietary intake of lung cancer cases compared with controls carefully matched for age, sex, ethnicity and smoking, SCHABATH et al [54] reported that consumption of phyto-oestrogens reduced lung cancer risk in a doseresponse relationship. Further analysis of this observation revealed that it was due to differences in consumption of soybean in particular, over that of fruit and vegetables, or lignin containing (tea and coffee) sources [54].…”

“…In a very detailed analysis of the dietary intake of lung cancer cases compared with controls carefully matched for age, sex, ethnicity and smoking, SCHABATH et al [54] reported that consumption of phyto-oestrogens reduced lung cancer risk in a doseresponse relationship. Further analysis of this observation revealed that it was due to differences in consumption of soybean in particular, over that of fruit and vegetables, or lignin containing (tea and coffee) sources [54]. While this apparent ''protective effect'' was evident in lifelong nonsmokers, it was two-fold greater in current and former smokers [54].…”